How to make it working?

[Janek1234]

Hello guys, I am begginer in Packet Tracer, I have a problem with overlapping on router interfaces, and i don't know why it happens, what they mean or how to prevent them.

The point of this topology is to can ping all devices from any of them also between VLANs, if you know what i mean guys.

When overlapping appreared, i didn't even try to configure 3rd interface on router, i think it would also overlap.

Guys i hope you can help me :)

[Seb Rupik]

Hi there,
Since you want to connect each switch to the router, you will not be able to use routed interfaces on the router, as you will encounter the issue of over-lapping interfaces subnets.

To achieve your topology you need to configure SVIs and trunk the required VLANs to the switches. Try the following:

!
no int fa0/0.10
default interface fa0/0
!
int vlan10 
  ip address 192.168.1.1 255.255.255.0
int vlan20 
  ip address 192.168.2.1 255.255.255.0
int vlan30 
  ip address 192.168.3.1 255.255.255.0
!
int range fa0/0-2
  no shut
  switchport
  switchport mode trunk
  switchport trunk allowed vlan 10,20,30
!

cheers,

Seb.

[Mark Malone]

Hi
You are creating 2 interface there , 1 physical and 1 sub interface
1 of them is in vlan 1 default as 192.168.1.x /24 F0/0

Now you have also created vlan 10 with same ip range 192.168.1.x/24 in fa0/0.10 ,You cannot do this , 2 interfaces cannot have the same IP address on the same router , say an end user that sends a packet out to the 192.168.1.x network the router wont know which interface to send it out , so its preventing that mistake as its all the same global routing table , if the interfaces were segregated through a VRF you can have same ip addresses multiple interfaces as there are multiple routing tables

You could change it to say 192.168.2.x /24 , vlans must have different subnets

please read this quick doc , it explains the design your trying to achieve in sections it may help further

http://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/336-cisco-router-8021q-router-stick.html

[Janek1234]

Where exactly to type these commands? and how i should configure switches?
i did switches like this:

conf term

i.g. interface fa0/1
switchport mode access
switchport access vlan 10
no shutdown
exit
and so on,
fa0/4 is switchport mode trunk
and all of the PCs have IPs like horizontally 192.168.1.2 192.168.2.2
192.168.3.2

192.168.1.3 192.168.2.3 and ....

[Seb Rupik]

Hi there,

The commands I specified earlier must be typed on the router.

Assuming that switch1 is connected to fa0/0, switch2 is connected to fa0/1 and switch3 is connected to fa0/3.

Taking switch1 as an example, lets assume it has the following connectivity:

Fa0/0  -- connects to router fa0/0

fa0/1 -- connects to PC1 (192.168.1.2)

fa0/2 -- connects to PC1 (192.168.2.2)

fa0/3 -- connects to PC1 (192.168.3.2)

...you would need the following configuration:

!
vlan 10
vlan 20
vlan 30
!
int fa0/0
  switchport mode trunk
  switchport trunk allowed vlan 10,20,30
!
int range fa0/1-3
  switchport mode access
  spanning-tree portfast
  no shut
!
int fa0/1
  switchport access vlan 10
int fa0/2
  switchport access vlan 20
int fa0/3
  switchport access vlan 30
!

Hope that helps.

cheers,

Seb.

[Janek1234]

Yea but i typed these commands and half of them were likw invalid or sth i
mean some error aleared i ll tell you more about this when i am back from
school so i hope we will work this out:) cheers